This invention is generally concerned with printing apparatus and more particularly with printing apparatus having a security device for detecting attempts at unauthorized access to the printing apparatus.
As shown in U.S. Pat. No. 4,168,533 for a Microcomputerized Miniature Postage Meter, issued Sep. 18, 1979 to Schwartz and assigned to the assignee of the present invention, it is known in the art to provide portable ink jet printing apparatus for applying postage indicia to an envelope for creating a mailpiece. Moreover, as shown in U.S. Pat. No. 4,739,343 for a Thermal Printing System for Postage Meter Mailing Machine Application, issued Apr. 19, 1988 to Dolan and assigned to the assignee of the present invention, it is known in the art to provide printing apparatus which includes a thermal print head for printing alphanumeric and graphic information, including postage indicia, on a substrate which has been treated to be responsive to being brought into contact with the print head. And, as shown in U.S. Pat. No. 4,802,218 for an Automated Transaction System, issued Jan. 31, 1989 to Wright, et. al., it is known in the art to provide portable accounting structure, including a hand held card having embedded therein a microprocessor for storing a predetermined postage value and accounting for dispensing increments of the stored value by associated, non-portable, printing structure.
Other prior art materials of interest, which were found in the course of a search concerning the present invention, include: European Patent Application Publication No. 0 480 749 A1 for a Franking Machine and Method Of Forming Franking Impression, filed Oct. 11, 1991 as Application No. 9 1309379.5 by Alcatel Business Systems and published Apr. 15, 1992; U.S. Pat. No. 4,933,706 for a Franking Machine, issued Jun. 12, 1990 to Abumehdi; U.S. Pat. No. 4,978,839 for a Postage Meter Value Card System, issued Dec. 18, 1990 by Chen, et. al.; and U.S. Pat. No. 5,227,614 for a Core Computer Processor Module and Peripheral Shell Module Assembled To Form A Pocket Size Data Capture Unit, issued Jul. 13, 1993 Danielson, et al.
On the other hand, the prior art appears to be silent regarding the provision of thermal printing apparatus, which includes a security device for easily detecting attempts at unauthorized access to the printing apparatus and for indicating such unauthorized access attempts as part of the printed indicia.
Since enhanced security of postage meters is extremely desirable as discussed in the Government Accounting Office report GAO/GD-94-148 of May 1994 entitled "POSTAGE METERS Risk of Significant Loss But Controls Are Being Strengthened", improved apparatus for detecting attempts at unauthorized access to postage meters is highly desirable. Accordingly, an object of the invention is to provide a security device for a printing apparatus which readily detects attempted unauthorized access to the printing device. Still another object of the invention is to provide a display of such attempts at unauthorized access of the postage meter as part of the printed indicia.